Crude oils contain a complex mixture of different hydrocarbons of varying lengths and complexities. Crude oils also contain varying amounts of different contaminants, including, for example, organic acids and bases, inorganic acids and bases, metals, metalloids, and entrained particulates. Contaminants have potentially profound, deleterious impacts on refining processes and refinery equipment. As just one example, highly acidic crude oils lead to premature corrosion of refining equipment. The acidity of a crude oil is typically measured as the Total Acid Number (TAN), and it is generally desirable to reduce the TAN of a crude oil early in the refining process. In fact, because of the potential damage contaminated crude oils can cause, commercial refineries will reject crude oils exhibiting undesirably high levels of harmful contaminants, such as crude oils exhibiting high TAN values and/or crude oils containing high levels of certain metal, metalloid, or particulate species.
The nature and relative amounts of hydrocarbon components and the contaminant profile of crude oils vary tremendously, with crude oils derived from different materials, processes, and geographic locations exhibiting unique hydrocarbon and contaminant profiles. However, synthetic crude oils can exhibit particularly challenging contaminant profiles, often exhibiting high TAN values and including relatively high concentrations of one or more metal, metalloid, or particulate contaminants.